Agitator



.Patented May 1, 1928.

UNITED STATES PATENT OFFICE.

EDGAR B. NICHOLS, OF ROCHESTER, NEW YORK, ASSIGNOR T0 THE PFAUDLER COI- PANY, O1? ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

Lennon.

Application filed October 31, v1924. Serial Io. 747,118.

rIhis invention relates to agitators for stirring or working materials as, for example, the iuid contents of a processing container, and, more particularly, to agitators of the variety adapted to have a lieatin or cooling medium circulated therethrough or the purpose of controlling the temperature of the material being treated. One object of the invention is to -provide an improved agitator of this character having a more practical form of construction as regards not only its agitating function but also the efficient transfer of heat between it and the material upon which it operates. More specifically, it is an object of the invention to provide a rotary device of the class described having a form of construction efficiently adapted to produce the desired agitation and comprising a substantial operating surface or area with means for heating all portions thereof uniformly during rotation to v accomplish the rapid transfer of heat to or from' the .material while agitating the same. A further object is to provide in combination with such an agitator a construction especially adapted for the application thereto of a protective coating of glass or other vitreous material for resisting the action of acids and other corrosive liquids.v Still a further object isto provide an agitator embodying the above features in a forni of construction and arrangement of parts whichl is practical and economical from the standpoint of manufacture and operation.

To these and other ends the invention resides in certain improvements and combina-- tions of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings: Figure 1 is a central sectional view of an agitating device embodying the present invention and showing theasame applied to a processing container or tank;

Figure 2 is a front view of the agitatorl proper, and

Figure 3 is an enlarged sectional view on the line ia-3 in/Figure 2. f

Similar reference numerals throughout the several views indicate the same parts. The preferred embodiment of the invention herein disclosed by way of illustration vof the principles involved, shows the application of the saine to an agitator of the screw propeller type, but the novel principles are applicable as well to agitators in radial or other directions, as will more clearl appear as the description proceeds.`

Re erring more particularly to the draw- 1ng there is shown at 5 a vat or tankof the variety, for example, commonly employed in processing operations requiring agitation and control of the temperature of thematerial under treatment. The tank wall has an opening 6 therein receiving the agitator bearing 7, the axis of which may extend horizontally, or vertically, or in any desired direction. The bearing has a flange 8 secured to the wall of the tank as by means of bolts 9 with an interposed packing to make a Huid tight connection. Rotating in bearing 7 isan elongated hub sleeve 11 and supported in the latter by means presently to be described is a concentrically spaced inner sleeve 12 which with sleeve 11 forms a portion of the hub of the agitator proper now to be described.

The agitator is in the presentinstance, as,

stated, of the screw propeller type comprising blades extending outwardly from the hub and eiiiciently shaped for producing by rotation an agitating circulation of the material. The agitator or propeller is of hollow .construction and a heating or coolin medium is supplied to its interior throug the hub sleeves for controlling the temperaagitator which is easy to manufacture into the desired lshape and at the same time l'affords the desired hollow construction throughout with thin walls for heat trans mission. To this end they invention com'- prises the usey of a pair` of sheet metal plates 13 and ll'forming, respectively, the

front and rear of the agitator or propeller;v

These plates are readily cut vfrom sheety metal and stamped up to forml a plurality of propeller bla/des to which any efficient propelling shape may thus easily be applied.

The plates are so formed or curved as lto bring'their'marginal portions together about the peripheries of the blades where the edges are soldered, welded or otherwise joined as indicated at 15 to form a fluid tight hollow body. The walls of the blades inwardly from their peripheries and adjacent the center or hub of the agitator are spaced apart as shown to provide space for the circulation 1n substantial volume of a heating or cooling medium supplied as hereafter described.

The central portion of plate 14 has an opening cut therein, the edges of which are fitted to a shoulder 16 of a cone shaped member 17' threadedly secured on the end of hub sleeve 11. This attachment of the plate to the hub sleeve is made fluid tight and it will be seen that the interior of the propeller and its blades between the spaced plates 13 and 14 is in communication with the bore of hub sleeve l1 around the inner sleeve 12. Member 17 abuts the end of bearing 7, thereby preventing axial movement of the propeller in one direction.

It has furthermore been found advantageous, especially in the use of a liquid or condensing fluid such as steam as a temperature controlling medium, to connect one of the fluid passages of the hub with the tips of the blades, for discharging the liquid or condensate when the agitator is so used as to t'end to collect the same at these points.

To .this end the front plate 13 of the propeller 1s preferably constructed with a flat central portion 18 to which is soldered, welded or otherwise fixed in fluid tight relation, a`

substantially cup shaped member 19 having a central flanged opening 20 the flange of which is threadedly engaged with the extended end of the inner hub sleeve 12. Member 19 has fixed in its wall opposite each of the propeller blades, one or more tubular conductors 21 which extend outwardly in the blades and communicate with the interior space of the latter adjacent their tips. It is thus apparent that the conducting means or tubes 21 serve to conduct fluid from the tips of the blades to the hub passageway formed by the bore of the inner sleeve 12. Thus one hub passageway communicates with the` interior of the blades adjacent their bases at the hub while the other passagewa communicates with the interior of the bla es adjacent their tips.

The plates from which the agitator is constructed may be of a corrosion resisting metal or of a suitable metal having an outer coatin of glass or other vitreous material applic thereto for protecting it against corrosive action. The hollow sheet metal construction described possesses not only the advantage of being readily manufactured in a desired shape and of affording an efficient t heat transferring body but also the additional advantage of being especially adapted for fusing thereon of a vitreous coating, by reason of the fact that it is hollow throughout with thin walls and a venting opening, which features contribute to the etcient fusing thereon of a vitreous coating. as well understood in the art.

The hub passages are provided with conducting connections comprising a bearing 22 for the opposite end of hub sleeve 11 which terminates as shown at 23 intermediate the ends of the bearing opening. Screwed into the bearing and communicating with its bore or opening is a pipe 2l through which fluid may be conducted to or from sleeve 11 about the inner sleeve 12 and therefore to or from the interior of the agitator. The inner sleeve 12 extends through bearing 22 and into a cup 25 screwed into the end of the bearing and serving also as a nut for compressing the packing material 2G about the sleeve in a packing chamber in bearing 22. Screwed into cup is a pipe 27 communieating through the cup with the interior of hub sleeve 12 and thence through the conductors 21 with the tips of the blades. Thus as the propeller is rotated, a heating or cooling medium may be supplied continuously through pipe 24 to the interior of the propeller at the base of the blades, such medium being thus applied to the entire active surface of the agitator to uniformly heat or cool it, the medium being returned through conductors 21 from the tips of the blades to pipe 27. The direction ot circulation may also be reversed from that described if so desired. As a matter of fact, where a liquid or steam is employed as a medium, it is preferred to employ pipe 24C and the bore of hub sleeve 11 as the inlet passage when the propeller is rotated at a high speed for the reason that liquid or condensation tends to collect at the tips of the blades under the action of centrifugal force. The outer ends of conductors 21 are thus advantageously positioned forv the discharge of the fluid after `it has heated the agitator through sleeve 12 under the pressure of the fluid supplied through sleeve 11. Where the speed of rotation is low it is desirable in some cases to reverse the direction of rotation so that the liquid to be discharged, flowing down the blades as they ascend, is collected at the hub and returned through the outer sleeve 11. The direction of circulation may also Abe affected by the position in which the propeller is arranged in use, but in any condition and wherever the fluid to 'be discharged may tend to collect, its discharge may be efficiently accomplished by selection of the direction ot' circulation.

The agitator is rotated in the )resent instance by a gear 28 keyed on hu sleeve 11 adjacent the outer end of bearing 7 which is formed with a gland 29 for suitable packuse in conjunction with processing containers for the reason that it not only affords efficient agitating means but also a heater located interiorly of the material to be treated away from the container shell, so that all of the heat is transferred directly to the material without appreciable loss. At the same time the combination of the heater with the agitator provides for the transfer of heat to the material by a surface moving through the material continuously at relatively high speed and thus in rapidly successive Contact with all portions of the material so that the heating agitator may be maintained at the highV temperature which is most efficient for the transfer of heat, without danger of injuring the material. This form of construction provides for uniform heating of the entire active surface of the agitator and for the efficient removal of the circulating medium, so that a condensing medium as steam, for example, may be cooled below its condensing point and all of its heat transferred to the material. The construction furthermore lends itself effil ciently to the fusing of a vitreous coating on f gether about the periphery of the blades, one

of said plates being secured to said hub with the interior of the blades in communication with one of said hub passages, and conducting means communicating with the interior of each blade adjacent its tip and with the other of said hub passages.

2. A rotary agitating and temperature controlling device for a container comprising a hub formed by spaced inner and outer sleeves concentrically arranged to provide inlet and outlet passages, a plurality of hollow blades formed from a pair of spaced, sheet metal plates joined together about the periphery ofthe blades, said plates respectively being secured to said sleeves `with the interior of each blade adjacent its base in communication with one of said hub passages, and a conductor in each bladefcommunicating with the interior of the latter adjacent its tip and with the other of said passages.

3. In a device of the class described, a

support, a bearing secured thereon, a hollow blade having front and rear wall portions, the latter being free to rotate upon the bearing, a driving sleeve for the blade rotatable within the bearing, and a member extending within said sleeve and connected therewith and with the front wall portion of the blade.

4. In a device of the class described, a support, a bearing secured upon the support, a hollow blade having front and rear walls,

the latter being rotatably seated upon one end of the bearing, a sleeve rotatable within the `bearing and operatively connected with the blade, and a member extending within the sleeve and connected with the front wall of the blade.

v 5. In a device of the class described, a

support, a bearing secured upon the support, a hollow blade having front and rear walls, the latter being rotatably seated upon one end of the bearing, a sleeve rotatable within the bearing and operatively connected with the blade, a tube extending within the sleeve and connected with the front wall of the blade, and a member within the blade adapted to establish communication between the blade and said tube.

v 6. A rotary agitator comprising a plurality of hollow blades formed of front and rear plates, each plate havinga central hub portion, a tubular member connected with the rear hub portion and a second tubular member projecting through the first member and connected with the front hub portion.

7. A rotary agitator comprising a plurality of hollow blades formed of front and rear plates, each plate having a central hub portion, a tubular member connected with the rear hub portion, a second tubular member extending through the first member and conneeted with the fronthub portion and con'- duits projecting within the blades from one of said tubular members and communicating with the latter.

8. A rotary agitator comprising a plurality of hollow blades formed of front and rear plates, each plate having a central hub portion, a tubular member connected with the rear hub portion, a hollow member secured upon the front hub portion, a tubular member projecting 4through the first mentioned tubular member and connected with said hollow member and liquid circulating conduits extending within the blades and having their inner ends connected with said hollow member.

9. In/ combination, a receptacle, a bearing connected therewith, a rotary agitator Within the receptacle comprising a plurality 0f hollowblades formed of front and rear plates, each plate having a central hub portion, a

rear plates, inner and outer tubes, the outer tube having its inner end connected with the rear plate and the inner tube having its inner end connected with said front plate and conduits extending from said Inner tube within the blades and adapted to establfsh communication between the blades and said inner tube.

11. A rotary agitator comprising a tubular member, a plurality of hollow blades formed of front and rear plates, the rear plate of wlicb. is connected with one end of said tubular member, said blades divergin outwardly from said tubular member anil havingtheir tips in a transverse plane intersecting the axis of the tubular member in advance thereof, a second tubular member projecting through the first member and connected with said front plate in advance of the first mentioned tubular member and a plurality of separate conduits radiating from the second mentioned tubular member and havinor their outer ends terminating within the blades in advance of said tubular members.

EDGAR B. NICHOLS. 

